Fire alarm switch



pri 7, 1936. P. G, BAcKEs FIRE ALARM SWITCH Filed April l5, 1935 Invenlo j? 5@ c/re@ A Homey Patented Apr. 7, 1936 UNITED STATES PATENT OFFICE 1 Claim.

This invention relates to new and useful improvements in fire alarm switches.

The principal object of the present invention is to provide a re alarm switch which will be positive and substantially foolproof in operation.

Other important objects and advantages of the invention will become apparent to the reader of the following specification.

In the drawing:

Figure 1 represents a perspective view of an attic Wired to accommodate the present invention shown installed therein.

Figure 2 represents a front elevational View of the switch.

Figure 3 represents a longitudinal section view through the switch.

Referring to the drawing wherein like numerals designate like parts, it can be seen in Figure 1 that numeral 5 generally refers to the attic of a 2 dwelling house with numeral 6 indicating the rafters. Staples I are driven into the rafters and trained through these staples is the elongated strand 8, one end of which is anchored as at 9. The other end of this strand connects to the con- 2 tact III of the switch generally referred to by numeral I I.

This switch II consists of the shell I2 of current conductive material having the plunger I3 movably mounted therein. This plunger I3 has 30 a stop head I4 at its lower end and a reduced extension I5 at its opposite end. The reduced extension defines a shoulder I6 and extends through the screw bushing II. The upper end of the plunger which is of dielectric material is provided with the contact head I8 having an eye I9 thereon with which the cord or strand 8 connects.

A coiled extensible spring is interposed between the shoulder I6 and the bushing il and serves to snap the plunger downwardly so that 40 the contacts I8 will engage the Contact bushing I1 quickly.

Further referring to Figure 1, it can be seen that numeral 2l represents a wall socket with which a plug 22 can be engaged. Numeral 23 (Cl. ZOO-142) represents a step down transformer with which the cord of the plug 22 is connected and from the secondary of this transformer 23, one wire extends to one side of the alarm 25 while the other side of the transformer extends by way of 5 the wire to the contact head I8. The other side of the alarm 25 is connected by the wire 26 to the shell I2, as is clearly shown in Figure 2.

It can now be seen, that in the event the strand 23 is broken or burned through, it will be released 10 and the spring 20 will drop the plunger I3 rapidly so that the contact I8 will engage the contact plug IT and thus close the circuit including the alarm 25 so that the latter will be sounded and occupants of the house notified of the conflagra- 15 tion.

While the foregoing speciiication sets forth the invention in specific terms, it is to be understood that numerous changes in the shape, size and materials may be resorted to without departing 20 from the spirit or scope of the invention as claimed hereinafter.

Having thus described the invention, what is claimed as new is:

A circuit closing means comprising an elon- 25 gated strand anchored at one end, a switch, said switch consisting of a current conductive shell, means for supporting the shell, a plunger slidable through the shell and being of dielectric material, said plunger at one end being provided with a stop head for engagement against one end of the shell, a bushing disposed within the opposite end of the shell, said plunger being provided with a reduced extension for disposition through the bushing, a coiled spring in the shell interposed between the bushing and the shoulder defined by the reduced portion of the plunger, said reduced portion of the plunger having a threaded extremity, a contact head provided with a threaded recess for receiving the threaded portion of the plunger, said contact head being adapted to engage the bushing and a connection between the strand and the said contact head.

PETER G. BACKES. 

